1. Technical Field of the Invention
The present invention relates to a method for the synchronous transmission of binary digital signals through a bus and also relates to a circuit system for implementing this method.
2. Description of the Related Art
In the design of complex digital electronic systems comprising various devices connected to each other by means of transmission bus-lines it is well known that the number of transitions of the data sent on the bus (bus switching activity) has a considerable effect on the overall energy consumption of the system.
Various techniques are known for reducing the bus switching activity that are based on encoding the data to be transmitted. The techniques most widely employed with small buses, for example up to eight leads for the transmission of a like number of binary digital signals (bits), make a comparison between two successive logic states of the bits to be transmitted. If the comparison shows that half, or less than half, of the bits have to pass from one state to the other, the bits are routed on the bus without any intervention. However, if more than half the bits have to pass from one state to the other, all the bits are inverted before they are routed. In this way the number of transitions on the transmission bus is minimized (Bus-Invert Coding) and the energy consumption is limited.